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Biomedical subjects

C A Pierson

Publications and source records attributed to C A Pierson.

At least 19 recordsLinked to original sources
PubMed1999

Ethnomethodologic analysis of accounts of feeding demented residents in long-term care.

PURPOSE: To describe the self-organizing activities and the unspoken knowledge that nursing assistants employ in performing the work of feeding as a routine part of their activities. In U.S. long-term care facilities, activities related to medical and nursing care are frequently based on the ability of nursing assistants to successfully accomplish the work of feeding. Nurses are not always aware of the difficulties involved in feeding nor the means by which food is offered and intake calculated. DESIGN: Qualitative phenomenologic. METHODS: Observations were conducted during 12 weekday mealtimes, October and November 1994. Data were collected using participant observation of mealtimes in the congregate dining room of one licensed long-term care facility. Data were analyzed using the framework of ethnomethodology to indicate the methods nursing assistants used to make sense of their interactions with demented residents. FINDINGS: Nursing assistants used several common behaviors: grouping the "difficult feeders" together; "marking the borders" by maintaining a tidy tray; and "loading the spoon" to maximize the amount of food given at one time. Estimations of the quantity of intake varied according to ideas about the nutritional content of various foods. CONCLUSIONS: Unsuccessful feeding interactions have implications for the quality of life for the demented. When inadequate intake leads to significant weight loss, medical and nursing interventions should be implemented.

Dementia↗
PubMed1997

A yeast sterol auxotroph (erg25) is rescued by addition of azole antifungals and reduced levels of heme.

Genetic disruption of the Saccharomyces cerevisiae C-4 sterol methyl oxidase ERG25 gene leads to sterol auxotrophy. We have characterized a suppression system that requires two mutations to restore viability to this disrupted strain. One suppressor mutation is erg11, which is blocked in 14alpha-demethylation of lanosterol and is itself an auxotroph. The second suppressor mutation required is either slu1 or slu2 (suppressor of lanosterol utilization). These mutations are leaky versions of HEM2 and HEM4, respectively; addition of exogenous hemin reverses the suppressing effects of slu1 and slu2. Suppression of erg25 by erg11 slu1 (or erg11 slu2) results in a slow-growing strain in which lanosterol, the first sterol in the pathway, accumulates. This result indicates that endogenously synthesized lanosterol can substitute for ergosterol and support growth. In the triple mutants, all but 1 (ERG6) of the 13 subsequent reactions of the ergosterol pathway are inactive. Azole antibiotics (clotrimazole, ketoconazole, and itraconazole) widely used to combat fungal infections are known to do so by inhibiting the ERG11 gene product, the 14alpha-demethylase. In this investigation, we demonstrate that treatment of the sterol auxotrophs erg25 slu1 or erg25 slu2 with azole antibiotics paradoxically restores viability to these strains in the absence of sterol supplementation via the suppression system we have described.

Antifungal Agents↗
PubMed1996

Cloning and characterization of the Saccharomyces cerevisiae C-22 sterol desaturase gene, encoding a second cytochrome P-450 involved in ergosterol biosynthesis.

The ERG5 gene from Saccharomyces cerevisiae was cloned by complementation of an erg5-1 mutation using a negative selection protocol involving screening for nystatin-sensitive transformants. ERG5 is the putative gene encoding the C-22 sterol desaturase required in ergosterol biosynthesis. The functional gene was localized to a 2.15-kb SacI-EcoRI DNA fragment containing an open reading frame of 538 amino acids (aa). ERG5 contains a 10-aa motif consistent with its role as a cytochrome P-450 (CyP450) enzyme and is similar to a number of mammalian CyP450 enzymes. Gene disruption demonstrates that ERG5 is not essential for cell viability.

Amino Acid Sequence↗
PubMed1996

Cloning and characterization of ERG25, the Saccharomyces cerevisiae gene encoding C-4 sterol methyl oxidase.

We have cloned the Saccharomyces cerevisiae C-4 sterol methyl oxidase ERG25 gene. The sterol methyl oxidase performs the first of three enzymic steps required to remove the two C-4 methyl groups leading to cholesterol (animal), ergosterol (fungal), and stigmasterol (plant) biosynthesis. An ergosterol auxotroph, erg25, which fails to demethylate and concomitantly accumulates 4,4-dimethylzy-mosterol, was isolated after mutagenesis. A complementing clone consisting of a 1.35-kb Dra I fragment encoded a 309-amino acid polypeptide (calculated molecular mass, 36.48 kDa). The amino acid sequence shows a C-terminal endoplasmic reticulum retrieval signal KKXX and three histidine-rich clusters found in eukaryotic membrane desaturases and in a bacterial alkane hydroxylase and xylene monooxygenase. The sterol profile of an ERG25 disruptant was consistent with the erg25 allele obtained by mutagenesis.

Amino Acid Sequence↗
PubMed1996

No small task.

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Activities of Daily Living↗
PubMed1995

An autosomal genetic linkage map of the sheep genome.

We report the first extensive ovine genetic linkage map covering 2070 cM of the sheep genome. The map was generated from the linkage analysis of 246 polymorphic markers, in nine three-generation full-sib pedigrees, which make up the AgResearch International Mapping Flock. We have exploited many markers from cattle so that valuable comparisons between these two ruminant linkage maps can be made. The markers, used in the segregation analyses, comprised 86 anonymous microsatellite markers derived from the sheep genome, 126 anonymous microsatellites from cattle, one from deer, and 33 polymorphic markers of various types associated with known genes. The maximum number of informative meioses within the mapping flock was 222. The average number of informative meioses per marker was 140 (range 18-209). Linkage groups have been assigned to all 26 sheep autosomes.

Animals↗
PubMed1995

130 kb of DNA sequence reveals two new genes and a regional duplication distal to the human iduronate-2-sulfate sulfatase locus.

Deficiency of IDs activity results in Hunter Syndrome (mucopolysaccharidosis type II), a fatal X-linked recessive disorder. We report characterization of 28 cosmids around the IDS locus in Xq28. Four overlapping cosmids have been sequenced in their entirety generating a 130-kb contig. These studies show the fine structure of the IDS gene and identify an IDS pseudogene-like structure located 20 kb distal to the active gene. Two novel genes have also been identified in this sequence, and one of these genes is also locally duplicated. Both homologs are expressed, and a number of alternative transcript products have been characterized. The presence of a highly conserved pseudogene-like structure within a larger duplicated region close to the IDS gene has significant implications for the study of mutations at this locus.

Base Sequence↗
PubMed1995

How low can you go?

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Health Benefit Plans, Employee↗
PubMed1995

On feeding the dog.

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Conflict, Psychological↗
PubMed1995

Moving In.

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Faculty, Nursing↗
PubMed1994

The identification of a gene family in the Saccharomyces cerevisiae ergosterol biosynthesis pathway.

The Saccharomyces cerevisiae ERG24 gene, encoding sterol delta 14 reductase (Erg24p), was cloned by selecting strains carrying sequences on a 2 mu-based vector for resistance to the morpholine fungicide, fenpropimorph (Fp). Four distinct plasmid inserts which conferred Fp resistance (FpR) were recovered (plasmids pML99, pML100, pML101 and pM103). Although Fp is reported to inhibit activity of Erg24p and sterol delta 8-delta 7 isomerase (Erg2p; encoded by ERG2), none of the inserts had restriction maps resembling ERG2. In addition, a 2 mu plasmid overexpression of the ERG2 sequence did not produce FpR. Characterization studies were focused on plasmid pML100, because it was the only plasmid to confer FpR consistently when tested in a number of different genetic backgrounds. Tests with a panel of fungicides indicated that pML100 conferred significant resistance only to compounds (Fp, tridemorph, fenpropidin and azasterol) which have a shared site of action, Erg24p. An insertional disruption of pML100 resulted in an obligate anaerobic phenotype, indicating a lesion in sterol biosynthesis. Sterol analysis of the disrupted mutant demonstrated the accumulation of ignosterol, indicating a loss of Erg24p activity. A SphI-XbaI fragment of pML100 was sequenced, revealing the presence of an ORF encoding a 438-amino-acid protein, which is highly similar to those encoded by two previously reported yeast drug sensitivity genes, sts1+ (Schizosaccharomyces pombe) and YGL022 (S. cerevisiae). Analyses of these genes demonstrated that strains carrying disruptions of sts1+ or YGL022 have ergosterol biosynthesis defects in the enzyme, sterol C-24(28) reductase (Erg4p; encoded by ERG4).(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1994

Sheep linkage mapping: nineteen linkage groups derived from the analysis of paternal half-sib families.

Nineteen linkage groups containing a total of 52 markers have been identified in the sheep genome after typing large paternal half-sib families. The linkage groups range in size from 2 markers showing no recombination to a group containing 6 markers covering approximately 30 cM of the sheep genome. Thirteen of the groups have been assigned to a sheep chromosome. Three groups contain markers from bovine syntenic groups U2, U7 and U29, and one other group contains a marker that has been mapped only in humans. The remaining three groups are unassigned. This information will provide a useful foundation for a genetic linkage map of sheep.

Animals↗